• Biomolecules & Therapeutics
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• v.29 no.2
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• pp.144-153
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• 2021

Astrocytes play various important roles such as maintaining brain homeostasis, supporting neurons, and secreting inflammatory mediators to protect the brain cells. In aged subjects, astrocytes show diversely changed phenotypes and dysfunctions. But, the study of aged astrocytes or astrocytes from aged subjects is not yet sufficient to provide a comprehensive understanding of their important processes in the regulation of brain function. In this study, we induced an in vitro aged astrocyte model through late passage cultivation of rat primary cultured astrocytes. Astrocytes were cultured until passage 7 (P7) as late passage astrocytes and compared with passage 1 (P1) astrocytes as early passage astrocytes to confirm the differences in phenotypes and the effects of serial passage. In this study, we confirmed the morphological, molecular, and functional changes of late passage astrocytes showing aging phenotypes through SA-β-gal staining and measurement of nuclear size. We also observed a reduced expression of inflammatory mediators including IL-1β, IL-6, TNFα, iNOS, and COX2, as well as dysregulation of wound-healing, phagocytosis, and mitochondrial functions such as mitochondrial membrane potential and mitochondrial oxygen consumption rate. Culture-conditioned media obtained from P1 astrocytes promoted neurite outgrowth in immature primary cultures of rat cortices, which is significantly reduced when we treated the immature neurons with the culture media obtained from P7 astrocytes. These results suggest that late passage astrocytes show senescent astrocyte phenotypes with functional defects, which makes it a suitable model for the study of the role of astrocyte senescence on the modulation of normal and pathological brain aging.

• Biomolecules & Therapeutics
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• v.31 no.1
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• pp.116-126
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• 2023

Mainly due to the slanted focus on the mechanism and regulation of neuronal aging, research on astrocyte aging and its modulation during brain aging is scarce. In this study, we established aged astrocyte culture model by long-term culturing. Cellular senescence was confirmed through SA-β-gal staining as well as through the examination of morphological, molecular, and functional markers. RNA sequencing and functional analysis of astrocytes were performed to further investigate the detailed characteristics of the aged astrocyte model. Along with aged phenotypes, decreased astrocytic proliferation, migration, mitochondrial energetic function and support for neuronal survival and differentiation has been observed in aged astrocytes. In addition, increased expression of cytokines and chemokine-related factors including plasminogen activator inhibitor -1 (PAI-1) was observed in aged astrocytes. Using the RNA sequencing results, we searched potential drugs that can normalize the dysregulated gene expression pattern observed in long-term cultured aged astrocytes. Among several candidates, minoxidil, a pyrimidine-derived anti-hypertensive and anti-pattern hair loss drug, normalized the increased number of SA-β-gal positive cells and nuclear size in aged astrocytes. In addition, minoxidil restored up-regulated activity of PAI-1 and increased mitochondrial superoxide production in aged astrocytes. We concluded that long term culture of astrocytes can be used as a reliable model for the study of astrocyte senescence and minoxidil can be a plausible candidate for the regulation of brain aging.

• BMB Reports
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• v.48 no.12
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• pp.696-701
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• 2015

Toll-like receptor 3 (TLR3) recognizes viral double-stranded RNA. It stimulates pro-inflammatory cytokine and interferon production. Here we reported the expression of a novel isoform of TLR3 in human astrocyte cell lines whose message is generated by alternative splicing. The isoform represents the N-terminus of the protein. It lacks many of the leucine-rich repeat domains, the transmembrane domain, and the intracellular Toll/interleukin-1 receptor domain of TLR3. Type I interferons (interferon-α and interferon-β) induced the expression of this isoform. Exogenous overexpression of this isoform inhibited interferon regulatory factor 3, signal transducers and activators of transcription 1, and Inhibitor of kappa B α signaling following stimulation. This isoform of TLR3 also inhibited the production of chemokine interferon-γ-inducible protein 10. Our study clearly demonstrated that the expression of this isoform of TLR3 was a negative regulator of signaling pathways and that it was inducible by type I interferons. We also found that this isoform could modulate inflammation in the brain.

• Parasites, Hosts and Diseases
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• v.48 no.1
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• pp.15-21
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• 2010

Astrocytes are the most abundant cells in the central nervous system that play roles in maintaining the blood-brain-barrier and in neural injury, including cerebral malaria, a severe complication of Plasmodium falciparum infection. Prostaglandin (PG) $D_2$ is abundantly produced in the brain and regulates the sleep response. Moreover, $PGD_2$ is a potential factor derived from P. falciparum within erythrocytes. Heme oxygenase-1 (HO-1) is catalyzing enzyme in heme breakdown process to release iron, carbon monoxide, and biliverdin/bilirubin, and may influence iron supply to the P. falciparum parasites. Here, we showed that treatment of a human astrocyte cell line, CCF-STTG1, with $PGD_2$ significantly increased the expression levels of HO-1 mRNA by RT-PCR. Western blot analysis showed that $PGD_2$ treatment increased the level of HO-1 protein, in a dose- and time-dependent manner. Thus, $PGD_2$ may be involved in the pathogenesis of cerebral malaria by inducing HO-1 expression in malaria patients.

• The Journal of Internal Korean Medicine
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• v.22 no.3
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• pp.331-339
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• 2001

목적 : 본 연구는 식풍해경(熄風解痙), 소산풍열(疏散風熱) 효능이 있는 백강잠이 치매에 미치는 영향을 알아보기 위하여 실험을 행하였다. 방법 : 치매 유발물질인 $amyloid{\beta}(A{\beta})$ 25-35를 흰쥐의 뇌 astrocyte에 처리한 후 대표적인 항산화 효소인 catalase, superoxide dismutase,glutathione peroxidase 및 glutathione-S-transferase의 활성 변화와 NO 생성 변화를 관찰하였다. 결과 $A{\beta}$ 25-35 처리로 catalase와 superoxide dismutase 활성이 현저히 감소하였으나 백강잠을 처리한 경우는 이들 효소 활성이 크게 증가하였다. 그리고, $A{\beta}$ 25-35의 농도에 의존적으로 증가된 NO 생성은 백강잠의 농도에 의존적으로 유의성 있게 억제되는 것으로 나타났다. 결론 : 백강잠은 항산화계 효소의 활성화 및 $A{\beta}$처리와 같은 치매유발 물질의 독성에 대한 적응능력 향상을 통하여 astrocyte를 보호하는 효능을 가지는 것으로 사료되며, 아울러 노인성 치매 등 임상적 응용에 그 효과가 기대된다.

• Bulletin of the Korean Chemical Society
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• v.23 no.3
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• pp.363-364
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• 2002

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.135.3-136
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• 2003

Liriope platyphylla (LP) Wang et Tang has been used for tonic, anti-tussive and expectorant in Korea. In the current study, we found that buthanol fraction of Liriope platyphylla-conditioned media of C6 and primary astrocyte induced the neurite outgrowth of PC 12 cells, which effect was reversed by addition of NGF-antibody. We demonstrated that buthanol fraction of Liriope platyphylla increased the expression and secretion of NGF through RT-PCR and ELISA. (omitted)

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.374-380
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• 2009

Samryungbaikchul-san(SRBCS) has been used in oriental medicine for the treatments of gastrointestinal and neurological disorders. Here, potential protective function of SRBCS was investigated in neural tissues in Alzheimer's disease(AD) mouse model. In primary cultured cells from the spinal cord of newborn rats, treatment of ${\beta}$-amyloid peptide elevated cell counts positive to glial fibrillary acidic protein(GFAP) or caspase 3 immunoreactivity, but the co-treatment of SRBCS reduced positive cell counts. In vivo administration of scopolamine, an inhibitor of muscarinic receptor, resulted in increases in the number of glial fibrillary acidic protein(GFAP) and caspase 3-positive cells in hippocampal subfields, which was then decreased by the treatment of SRBCS or acetylcholinesterase inhibitor galathamine. The present data suggest that SRBCS may play a protective role in damaged neural tissues caused by scopolamine treatments in mice.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.1
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• pp.145-152
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• 2007

Following CNS injury, inhibitory influences at the site of axonal damage occur. Glial cells become reactive and form a glial scar, gliosis. Astrocyte-rich gliosis relates with up-regulation of GFAP and CD81, and eventually becomes physical and mechanical barrier to axonal regeneration. It is postulated that the astrocytic reaction is absent, regeneration of axons can occur. And it was reported that treatment with anti CD81 antibodies enhanced functional recovery in the rat with spinal cord injury. So in this current study, the author investigated the effect of the water extract of Persicae Semen on the regulation of GFAP and CD81 that increase when gliosis occurs. Persicae Semen decreased the expression of GFAP and CD81 in astrocyte cell by ELISA method. Persicae Semen decreased the RNA expression of CD81 and GFAP. The proteins that separate in whole cell were analaysed by western blot, and the expression of GFAP and CD81 was decreased. In vivo, rats brains were peformed cortical stab wound, the water extracts of Persicae Semen were injected for 7 days, 30 days. As a result, GFAP and CD81 expression were decreased in immunohistochemistry. These findings demonstrate that Persicae Semen decreases GFAP and CD81 expression. Accordingly, Persicae Semen could be a candidate for promotion of axon regeneration after CNS injury.

• The Korean Journal of Pharmacology
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• v.30 no.2
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• pp.167-179
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• 1994

Recent evidence indicates that glial cells have a wide range of funtions which are critical for maintaining a balanced homeostatic environment in the central nervous system(CNS) peripheral nervous system(PNS). Morever, astrocytes are known to participate in the tissue repair and neuroimmunologic events within the CNS through many kinds of growth factors and cytokines. We investigated the effect of $TGF\;{\beta}_1$, on the growth and biochemical changes of rat glial cells in culture. The proliferative effect was determined by $^3H-thymidine$ uptake and the double immunostain with anti-cell-specific marker and anti-Bromodeoxyuridine(BrdU) antibody. To check the effect of biochemical changes we compared the amounts of glial fibrillar acidic protein(GFAP) and the activity of glutamine synthetase(GS) in astrocyte. And the amounts of myelin basic protein and the activity of 2',3'-cyclic nucleotide phosphohydrolase(CNPase) were measured in oligodendrocyte and the amounts of peripheral myelin in Schwann cell. When $TGF\;{\beta}_1$, was treated for 2 days with cultured glial cell, $TGF\;{\beta}_1$, decreased the $^3H-thymidine$ uptake and proliferation index of double immunostain of astrocytes, which indicates the inhibition of astroglial DNA synthesis, but stimulated the growth of Schwann cell. Also, $TGF\;{\beta}_1$, decrease the GS activity and increased the amounts of GFAP in astrocyte. In the case of Schwann cells the amounts of peripheral myelin was increased when treated with $TGF\;{\beta}_1$. However, $TGF\;{\beta}_1$, didn't show any effect on the proliferation and biochemical changes in oligodendrocyte. These results suggest that $TGF\;{\beta}_1$, might have a critical action in the regulation of proliferation and biochemical changes in glial cells, especially astrocyte.